Generally, when performing groove processing or chamfering processing of an edge portion on a material to be cut, an electric tool called an electric trimmer is used. This kind of electric trimmer is configured to include, for example: a trimmer main body in which a drive motor is housed; a bit which can be attached/detached to/from the trimmer main body and which is rotatably driven by the drive motor; and a base that grips the trimmer main body to be capable of sliding movement in an axial direction. The base is a member that acts as a reference of the electric trimmer. In addition, disposed at an upper end position of the base is a ring that is only allowed to undergo rotatory motion at said upper end position. An inner peripheral surface of the ring has formed thereon a screw thread or a thread groove. On the other hand, an outer peripheral surface of the trimmer main body has formed thereon a thread groove or a screw thread that threads with the screw thread or the thread groove of the ring. The ring and the trimmer main body are threaded with each other, hence if the ring is rotated, the trimmer main body undergoes sliding movement in the axial direction of the base according to that rotary motion, and positional adjustment of the bit with respect to the base is performed.
A conventional electric trimmer having the above-mentioned basic configuration makes it possible for the bit to rotate by rotating the drive motor, whereby groove processing or chamfering processing of an edge portion can be performed on a material to be cut. Moreover, since the trimmer main body can be caused to undergo sliding movement in an axial direction with respect to the base and a cutting depth of the bit can be adjusted, it is made possible to easily perform groove processing of a desired depth.
Incidentally, in order to fix the trimmer main body at an arbitrary position of the base, installation of a fixing releasing mechanism is essential. For example, Patent Document 1 listed below describes an embodiment in which a lever type fixing releasing mechanism is provided to a base surrounding a trimmer main body (in Patent Document 1, the trimmer main body is indicated as a “cylindrical housing”).